1. Field of the Invention: This invention relates to a method for monitoring and/or controlling the discharge of effluent to a receiving stream of water in such a manner so as to assure the maintenance of pre-established water quality requirements, particularly, for example, compliance with regulatory water quality standards for the receiving waters downstream of the effluent discharge site. More particularly, the present invention provides for an effluent discharge control system including an algorithm using inputs corresponding to upstream water quality characteristics and flow rate, the characteristic of the effluent which is to be discharged, characteristics of the receiving water downstream of the effluent discharge site within the zone of influence, actual downstream water quality characterizes for comparison with a prescribed water quality characteristic, and site specific conditions of the receiving waters.
2. Description of the Prior Art: One of the most significant Governmental regulation governing the discharge of an effluent by anyone is the requirement for a basic level of effluent treatment. Effluent treatment at a basic level is defined by the best available treatment technology for the particular effluent. Whether it be municipal sewage or industrial wastewater, this level of treatment must be attained under any and all circumstances before site-specific flow based limitations can be considered for meeting water quality based limitations in the receiving body of water. It is under these conditions that real time water quality management, flow based limitations, or any other innovative treatment technology can be considered by the regulatory agencies in the permitting process.
Federal and State statutes regulate water quality standards for various bodies of water. The rationale used by the regulatory agencies to protect the designated use of a body of water is to determine the wasteload allocation for an effluent to be discharged based upon a 7-day consecutive set of site specific condition occurring once every ten years. This site specific condition along with a set of well known equations form the basis for the calculations to establish the level of pollutants that can be discharged to the receiving waters without violating any of the prescribed water quality standards. Thus, anyone, particularly a manufacturer, desiring to discharge effluent into a regulated receiving body of water must comply with applicable site specific water quality standards. To assure compliance with such standards, it is convenient to ascertain the quantity of the effluent to be discharged so that a flow rate of wastewater to be discharged can be established and still meet regulatory water quality criteria established for the receiving waters. Owing to the lag time necessary for assimilation of the effluent discharge to the receiving stream, real time control of an effluent discharge could not be reliably utilized. Because of such a time lag, assurances could not be given, for example, that instream water quality standards are met without deviation, and particularly when such standards are of a government regulation. In the case of a direct discharger who is meeting the technology based level of treatment but the quality of the effluent is not sufficient to protect the water quality standards of the receiving body of water, the regulatory agency is required to impose water quality based limits on the discharger.
The present invention seeks to provide a system to enable a discharger of effluent to protect the designated water quality standards in the receiving body of water. In the system of the present invention, water quality is monitored upstream and downstream of a point source discharge of effluent as well as other parameters, such as flow rate, and an analysis is made of the effluent so that the effluent can be discharged to the receiving water while protecting water quality standards in the receiving waters. Thus, the present invention seeks to provide an effluent management control which is unlike systems known in the art, because this invention seeks to utilize more of the available assimilative capacity of the receiving waters without violating any of the prescribed water quality standards. This is accomplished by inputs of characteristics of the effluent to be discharged and site specific characteristics of the receiving waters assimilative capacity on a real time basis. Such basis for an effluent management control is more realistic than current practice which uilizes the most critical set of conditions that may or may not exist simultaneously in the receiving waters once every ten years according to the 7-day consecutive set of site specific conditions. Examples of known wastewater control can be found in U.S. Pat. Nos. 3,929,017; 3,974,940; 4,295,197; 4,353,181; 4,386,409; 4,468,043; 4,700,568; and 4,708,021.